Transparent Internet Caching (TIC) is an established technology for improving web browsing performance and resource utilization. In TIC, data content can be stored at a transparent proxy server, such as e.g. a Hypertext Transfer Protocol (HTTP) cache, being transparent to an end-user. This is undertaken by intercepting the HTTP traffic and creating a local cache of often requested content typically identified by frequently accessed Uniform Resource Locators (URLs) pointing to the data content. The popular data content is thus transferred to the transparent proxy server from a web server originally providing the content.
For instance, a user at a client browses a web site of a newspaper and requests a particular web page, and is directed to an HTTP proxy where the requested resource in the form of the particular web page is provided, for instance by fetching the web page from a proxy cache, or the HTTP proxy turns to the a web server of the newspaper for the requested resource, receives the resource, and finally provides the resource to the client. The purpose of the proxy is to enhance the user's experience through the faster and better responses it can provide. Further, by caching frequently requested content, the web server is relieved from responding to the requests. The proxy is transparent to the user in that the user does not know (or cares) that he/she is communicating with the proxy, and not with the server. Thus, the transparent proxy server is commonly arranged in a communication path between the client/user and the web server with which the client wishes to communicate in order to reduce response time to the user requests.
Encryption of data traffic over the Internet has drastically increased during the last years. In HTTP 2.0 based on SPDY protocol, URLs are encrypted using Transport Layer Security (TLS) cryptographic protocols. A problem remains in that encryption of URL makes caching of data difficult since the transparent proxy server cannot identify the content.